diff --git a/.github/workflows/test-windows.yml b/.github/workflows/test-windows.yml
index c4b257833df..dd4deaf3395 100644
--- a/.github/workflows/test-windows.yml
+++ b/.github/workflows/test-windows.yml
@@ -86,7 +86,7 @@ jobs:
       with:
         path: winbuild\build
         key:
-          ${{ hashFiles('winbuild\build_prepare.py') }}-${{ hashFiles('.github\workflows\test-windows.yml') }}-${{ env.pythonLocation }}-${{ steps.install.outputs.vs }}
+          z-${{ hashFiles('winbuild\build_prepare.py') }}-${{ hashFiles('.github\workflows\test-windows.yml') }}-${{ env.pythonLocation }}-${{ steps.install.outputs.vs }}
 
     - name: Prepare build
       if: steps.build-cache.outputs.cache-hit != 'true'
diff --git a/setup.py b/setup.py
index 6d3610098b8..ea5e23c1091 100755
--- a/setup.py
+++ b/setup.py
@@ -222,7 +222,11 @@ def _find_include_file(self, include):
 
 
 def _find_shared_library_file(self, library):
-    for dir_ in self.compiler.library_dirs:
+    if sys.platform == "win32":
+        dirs = (os.environ.get("PATH") or "").split(os.pathsep)
+    else:
+        dirs = self.compiler.library_dirs
+    for dir_ in dirs:
         libfile = os.path.join(
             dir_, self.compiler.library_filename(library, lib_type="shared")
         )